Hematological values and blood cell morphology of Ateles geoffroyi under human care in El Salvador

Abstract

Ateles geoffroyi is an endangered primate for which hematological assessment is critical to clinical diagnosis, welfare, and conservation under managed care. In El Salvador, species-specific data were lacking, hindering evidence-based interpretation. This study reports preliminary hematological reference values and blood cell morphology in healthy adult A. geoffroyi housed in three enclosures of the former National Zoological Park. We conducted a descriptive cross-sectional study of 15 individuals (10 males, 5 females). Approximately 0.5 mL of blood was collected from the medial saphenous vein; a complete blood count was performed and Wright– Giemsa–stained smears were examined. Minimum, maximum, and mean values were computed. Mean results were hemoglobin 12.29 g/dL, hematocrit 39.66%, erythrocytes 6.08 ×10⁵/mm³, platelets 286.8 ×10⁵/µL, and leukocytes 10.39 ×10⁵/mm³, with a lymphocyte-predominant differential and no relevant morphological abnormalities. Differences relative to regional reports likely reflect diet, parasitism, husbandry, and analytical methods. These findings provide a local reference baseline to support clinical evaluation and rehabilitation monitoring. Future research should expand sample size, standardize units (e.g., ×10³/µL), include absolute leukocyte differentials, and harmonize procedures according to international guidelines to develop robust regional reference intervals.